1. Department of Microbiology, Faculty of Science, Kasetsart University, Chatuchak, Bangkok 10900, Thailand
2. Department of Genetics, Faculty of Science, Kasetsart University, Chatuchak, Bangkok 10900, Thailand
3. Kitasato Institute for Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan